Model: PCI‑6521

Part Number: 779312‑01

Brand: National Instruments (NI)

Series: 652x Industrial Isolated DIO

Bus: PCI (5 V, half‑length)

Connector: 1 × 37‑pin D‑Sub (high‑voltage safety kit required)

Isolation: 60 V channel‑to‑channel isolation (DI); relay‑isolated (DO)

Driver: NI‑DAQmx

Operating Temp: 0 ~ 55 °C

Features: ±30 VDI, 150 V / 2 A relay DO, channel‑to‑channel isolation, watchdog, programmable power‑on, UL listed

I. Digital Inputs (DI) – 8 ch, isolated, sink/source

• Channels: 8 channel‑to‑channel isolated digital inputs

• Voltage Range: ±30 VDC

• Logic Thresholds: Low ≤ ±4 V, High < −11 V or > +11 V

• Input Type: sink or source configurable (24 V logic)

• Filtering: programmable debounce filters per channel

• Isolation: 60 V continuous, 620 Vrms (5 s) channel‑to‑channel

• Functions: change detection, event counting, status monitoring

II. Relay Outputs (DO) – 8 ch, non‑latching mechanical relay

• Channels: 8 non‑latching mechanical relay outputs

  • 3 × SPDT (Form C)

  • 5 × SPST (Form A)

• Switching Voltage: 150 VAC/VDC max

• Switching Current: 2 A / channel max

• Switching Power: 60 W / 60 VA max

• Power‑On State: programmable (open / closed)

• Life Cycle: 100,000 operations (resistive load)

• Functions: high‑voltage load switching, emergency cut‑off, safety interlocksNI

III. Industrial Features

• Watchdog Timer: 1–65535 ms; fault → safe state (open/closed)

• Programmable Power‑On: prevents unexpected actuation

• Channel‑to‑Channel Isolation: each DI isolated; relays isolate DO from system

• High CMR: robust for motors, inverters, relays

• UL Listed: UL 61010‑1 (IEC 61010‑1)

• Keyed & Shielded: safety connector + insulation covers

IV. Physical & Environmental

• Size: half‑length PCI, ~12.4 × 12.6 × 2.2 cm

• Weight: ~0.15 kg

• Temperature: 0 ~ 55 °C (oper), −20 ~ 70 °C (storage)

• Humidity: 10%–90%, non‑condensing

• Isolation Voltage: ≥ 60 Vrms (DI channel‑to‑channel); ≥ 500 Vrms (relay to system)

• Power: +5 V @ ~200 mA; +3.3 V @ ~300 mA

V. Wiring Highlights

• DI (sink/source): sensor to +24 V or GND; threshold ±4 V low / ±11 V high

• Relay DO: load between COM and NO/NC; max 150 V / 2 A

• Inductive loads: add 1N4007 freewheeling diode across coil

• Shielding: shield to isolated field ground, not system ground

• Safety: use NI high‑voltage safety kit (keyed cable, covers)

VI. Core Advantages & Applications

• 8 channel‑to‑channel isolated DI (±30 V, 60 V isolation) + 8 relay DO (150 V / 2 A)

• 150 V high‑voltage relays, true channel‑to‑channel DI isolation, watchdog, programmable power‑on, UL listed

• Ideal for 24 V sensor monitoring + high‑voltage (up to 150 V) load switching, industrial control panels, test stands, safety interlocks, power equipment controlNI